This invention relates to AMTI radar systems, and in particular to automatic means for improving the antijamming and interference and clutter rejection capabilities of such systems.
Radar systems of the type to which the adaptive clutter cancellation and interference rejection circuits of the invention can be applied are disclosed in U.S. Pat. Ser. No. 3,787,899, filed Nov. 7, 1972, by Carlyle J. Sletten et al., entitled AIRBORNE DIGITAL MOVING TARGET DETECTOR, and in U.S. Pat. Ser. No. 3,787,850, filed Nov. 7, 1972, by Carlyle J. Sletten et al., entitled AIRBORNE ANALOG MOVING TARGET DETECTOR.
There currently exists two basic problems that substantially reduce the effectiveness of these and other airborne radar systems. The primary problem is that of enemy jamming and interference from friendly as well as enemy RF sources that operate on the same frequency as the radar. The second problem is that of trimming phase and amplitude weights of the antenna element in order to overcome errors or show variations in these weights. These errors may be due to inaccurate calibrations, phase center measurements, or aircraft velocity measurements. The present invention is directed toward the solution of these particular problems with a concommitant improvement in the target-to-clutter ratio of the radar system.